1. Field of the Invention
The subject invention relates to a recliner assembly comprising a cam and a shaft having an annular shoulder, and more particularly, to an annular recess formed in the annular shoulder of the shaft that ensures consistent alignment of the cam against the annular shoulder when the cam is mounted to the shaft.
2. Description of the Prior Art
Automotive vehicles include seat assemblies for supporting occupants in the vehicle. The seat assemblies commonly comprise a seat cushion and a seat back. Typically, a recliner assembly operatively interconnects the seat back to the seat cushion and allows for angular adjustment of the seat back relative to the seat cushion between a plurality of reclined positions.
Disc recliners are well known in the vehicle seating art and are commonly used to pivotally interconnect the seat back to the seat cushion. An example of such a recliner assembly is shown in PCT application CA 99/00653, published Feb. 10, 2000. Disc recliners typically include cylindrical inner and outer discs rotatably coupled to one another. The inner and outer discs are adapted for fixed attachment to the seat cushion and seat back, respectively. Disc recliners further include a locking mechanism for selectively interlocking the inner and outer discs. The locking mechanism typically comprises an annular rim of teeth on the outer disc. Several pawls, each with a plurality of teeth, are nested within the inner disc. The pawls are moveable in a radial direction between a locked position and an unlocked position. With the pawls in the locked position, the teeth on the pawls are interlocked with the rim of teeth on the outer disc to prevent rotation of the outer disc relative to the inner disc. When the pawls are moved from the locked position to the unlocked position, the outer disc is freely rotatable relative to the inner disc. Typically, an input shaft is rotatably journaled to both the inner and outer discs. The input shaft is moveable between an unreleased position and a released position. A cam is fixedly assembled, usually by a press fit, to the input shaft for actuating the pawls between the locked and unlocked positions when the shaft is rotated between the unreleased and released positions, respectively.
To ensure proper engagement of the cam and the pawls, it is important both for the cam not to rotate relative to the shaft during actuation of the input shaft and for the cam to be properly aligned on the shaft. Typically, the cam and shaft are fixedly assembled in a splined relationship to prevent rotation of the cam relative to the shaft. Further, the shaft often has a shoulder for locating and aligning the cam onto the shaft during assembly of the cam and shaft. However, when the cam is pressed onto the shaft, displaced material scraped from the shaft can prevent the cam from properly aligning against the shoulder of the shaft.
Accordingly, there is a need for a shaft design that prevents material from the shaft, displaced during assembly of the cam onto the shaft, from interfering with the proper alignment of the cam on the shaft.
This invention relates to a recliner assembly that operatively interconnects a seat back and a seat cushion and allows pivotal adjustment of the seat back relative to the seat cushion between a plurality of reclined positions. The seat recliner assembly comprises an inner disc adapted for fixed attachment to the seat cushion. An outer disc, adapted for fixed attachment to the seat back, is pivotally coupled with the inner disc. A locking means is nested between the inner and outer discs. The locking means is moveable between a locked state, wherein the outer disc is prevented from rotating relative to the inner disc, and an unlocked state, wherein the outer disc is freely rotatable relative to the inner disc. A cam, disposed between the inner and outer discs, actuates the locking means between the locked and unlocked states. An input shaft is fixedly assembled to the cam and is rotatably journaled to both of the inner and outer discs. The input shaft comprises an annular shoulder for axially locating the cam along the shaft. The input shaft further comprises an annular recess formed in the annular shoulder for receiving displaced material from the input shaft formed during assembly of the cam to the input shaft, thereby allowing the cam to properly align against the annular shoulder of the shaft.